So far, there have been developed various types of plate holding apparatuses which are for holding a plate on a plate cylinder of a printing machine. For example, the Patent Document 1 discloses a plate holding apparatus designed such that a leaf spring for engaging a trailing edge end portion of a plate is provided along an axial direction of a tension bar and a lever fixedly secured onto an axial end portion of the tension bar is moved by a spring so as to rotate the tension bar so that the trailing edge end portion of the plate is drawn into a slit of a plate cylinder by the leaf spring to hold the plate on a circumferential surface of the plate cylinder.
In addition, the Patent Document 2 discloses a plate holding apparatus designed such that a leaf spring for engaging a trailing edge end portion of a plate is provided along an axial direction of a tension bar as well as the Patent Document 1 and a lever fixedly secured onto an axial end portion of the tension bar is moved by use of a working cylinder instead of a spring so as to rotate the tension bar so that the trailing edge end portion of the plate is drawn into a slit of a plate cylinder by the leaf spring to hold the plate on a circumferential surface of the plate cylinder.    Patent Document 1: Japanese Utility Model Laid-Open No. HEI 4-7133    Patent Document 2: Japanese Patent Laid-Open No. 2000-301694